NEET Thermodynamics — Set 10

Question 1

How much heat is required to raise the temperature of $ 0.5 \, \text{kg} $ of aluminium from $ 25^\circ \text{C} $ to $ 55^\circ \text{C} $? (Specific heat of aluminium = $ 900 \, \text{J kg}^{-1} \text{K}^{-1} $)

Accepted Answer

$ \Delta Q = m s \Delta T $. $ m = 0.5 $, $ s = 900 $, $ \Delta T = 55 - 25 = 30 $. $ \Delta Q = 0.5 \times 900 \times 30 = 13500 \, \text{J} $.

Question 2

What property distinguishes intensive variables from extensive variables?

Accepted Answer

Intensive variables (e.g., pressure, temperature) do not depend on the system’s size or amount, remaining unchanged when the system is divided. Extensive variables (e.g., volume, internal energy) scale with the system’s size.

Question 3

Which of the following statements is incorrect about internal energy?

Accepted Answer

Internal energy ($ U $) is the sum of molecular kinetic and potential energies, a state variable independent of the path. It does not include the system’s macroscopic kinetic energy (e.g., a moving bullet), making option C incorrect.

NEET Physics: Thermodynamics — Practice Set 10

Q1. How much heat is required to raise the temperature of \( 0.5 \, \text{kg} \) of aluminium from \( 25^\circ \text{C} \) to \( 55^\circ \text{C} \)? (Specific heat of aluminium = \( 900 \, \text{J kg}^{-1} \text{K}^{-1} \))

Q2. What property distinguishes intensive variables from extensive variables?

Q3. Which of the following statements is incorrect about internal energy?

Q4. A gas expands adiabatically from \( 3 \, \text{atm} \) and \( 6 \, \text{L} \) to \( 1 \, \text{atm} \). What is the final volume? (\( \gamma = 1.4 \))

Q5. What happens to the temperature of an ideal gas during an adiabatic expansion?

Q6. What is the molar specific heat capacity at constant pressure for a monatomic gas if \( C_v = 12.45 \, \text{J mol}^{-1} \text{K}^{-1} \) and \( R = 8.3 \, \text{J mol}^{-1} \text{K}^{-1} \)?

Q7. How much heat is required to vaporize \( 1.5 \, \text{g} \) of water at \( 100^\circ \text{C} \) and \( 1 \, \text{atm} \)? (Latent heat = \( 2256 \, \text{J/g} \))

Q8. A system releases \( 810 \, \text{J} \) of heat and has \( 270 \, \text{J} \) of work done on it. What is the change in internal energy?

Q9. Which of the following statements is incorrect about work in thermodynamics?

Q10. A gas at 5 atm in a 6 L container is heated from 20°C to 60°C at constant volume. What is the final pressure?